The present invention relates generally to elevator control systems and, in particular, to an apparatus and method for controlling an elevator in an energy conservation mode of operation.
In the past, elevators were adjusted to their maximum performance parameters, thus providing the most service during heavy usage periods. Unfortunately, the elevators ran with this level of performance all the time, regardless of the building needs.
In the U.S. Pat. No. 3,891,064, there is shown an elevator system that automatically switches between rated maximum performance and a reduced performance according to traffic conditions. The system normally operates at the rated maximum velocity and acceleration mode. When the demand for elevator service falls below a predetermined level, the velocity and/or the acceleration is reduced. The system includes a plurality of "traffic sensors" each of which causes switching from the reduced performance mode to the rated maximum performance mode when a predetermined traffic condition is sensed. The "traffic sensors" can include a clock that controls the switching according to traffic history.